"The following note was found appended to this passage in the handwriting of Mr. Knickerbocker. 'There has been much written against the divining rod by those light minds who are ever ready to scoff at the mysteries of nature; but I fully join with Dr. Knipperhausen in giving it my faith. I shall not insist upon its efficacy in discovering the concealment of stolen goods, the boundary stones of fields, the traces of robbers and murderers, or even the existence of subterranean springs and streams of water; albeit, I think these properties not to be readily discredited; but of its potency in discovering veins of precious metal, and hidden sums of money and jewels, I have not the least doubt. Some said that the rod turned only in the hands of persons who had been born in particular months of the year; hence astrologers had recourse to planetary influences when they would procure a talisman. Others declared that the properties of the rod were either an effect of chance or the fraud of the holder, or the work of the devil...."
The worthy and learned Mr. Knickerbocker might have gone on to quote authorities by the dozen. This weighty argument of his is not delivered with a wink to the reader. He is engaged in no solemn foolery. If one desires to find pirates' gold, it is really essential to believe in the divining rod and devoutly obey its magic messages. This is proven to the hilt by that very scholarly Abbé Le Lorrain de Vallemont of France whose exhaustive volume was published in 1693 with the title of La Physique Occulte, or "Treatise on the Divining Rod and its Uses for the Discovery of Springs of Water, Metallic Veins, Hidden Treasure, Thieves, and Escaped Murderers." In his preface he politely sneers at those scholars who consider the study of the divining rod as an idle pursuit and shows proper vexation toward the ignorance and prejudice which are hostile to such researches.
The author then indicates that the action of the divining rod is to be explained by the theory of Corpuscular Philosophy,[[1]] and by way of concrete argument, refers to the most famous case in the ancient annals of this art.
Methods of manipulating the diving rod to find buried treasure. (From La Physique Occulte, first edition, 1596.)
"It seems to me that my work would have been incomplete, had I not seen Jacques Aymar, and that the objection might have been raised that I had only argued about statements not generally accepted. This now famous man came to Paris on January 21st, 1693. I saw him two or three hours a day for nearly a month, and my readers may rest assured that during that time I examined him very closely. It is a positive fact that the divining rod turned in his hands in the direction of springs of water, precious metals, thieves, and escaped murderers. He does not know why. If he knew the physical cause, and had sufficient intellect to reason about it, I am convinced that, whenever he undertook an experiment he would succeed. But a peasant who can neither read nor write will know still less about atmosphere, volume, motion of corpuscles distributed in the air, etc. He is still more ignorant as to how these corpuscles can be disturbed and cease to produce the motion and dip of the rod. Neither is he capable of recognizing how essential to success it is for him to know whether he is in a fit condition to be susceptible to the action of the corpuscles which are thrown off from the objects toward which the rod inclines."
"I do not deny that there are cheats who profess belief in the rod, and put it to too many uses, just as quacks, with a good remedy for a special ailment, hold themselves up to contempt by wishing to palm it off as a cure-all. To this I add that people will be found who, endowed with greater and more delicate sensibility, will possess still more abundantly than he (Jacques Aymar) the faculty of discovering springs of water, metallic veins, and hidden treasure, as well as thieves and escaped murderers. We have already received tidings from Lyons of a youth of eighteen, who surpasses by a long way Jacques Aymar. And anyone can see in Paris to-day, at the residence of Mons. Geoffrey, late sheriff of that city, a young man who discovers gold buried underground by experiencing violent tremors the moment that he walks over it."